Defining brain death and the controversies of existence

The Boston Globe has an interesting article on the concept of ‘brain death’. The criteria for brain death are being contested and it’s become a hot issue, partly because the US allows organs from consenting donors to be removed when brain death has been diagnosed.

The ‘dead donor rule’ stipulates that it’s only possible to remove organs in cases where a person has died, and this can either be after cardiac death, where the heart and lungs stop functioning, or after brain death, where the brain suffers irreversible damage which causes coma where the patient is kept alive solely by life support.

Most organs donated from the deceased come from people who have been diagnosed as brain dead. Organs remain viable for only about an hour or two after a person’s last heartbeat. Brain dead patients are ideal candidates for organ donation, then, because they are kept on ventilators, which means their heart and lungs continue to work, ensuring that a steady flow of oxygen-rich blood keeps their organs healthy. Surgeons remove the donor’s organs, then shut off the ventilator. The patient’s heart eventually stops.

Yet a small but vocal minority in the medical community has always insisted that some brain dead patients may not be dead. For instance, one study documented some kind of brain activity in up to 20 percent of people declared brain dead, suggesting to some critics that doctors sometimes misdiagnose the condition. Although some neurologists contend the claim, University of Wisconsin medical ethicist Dr. Norman Fost points to research showing that many “brain dead” patients have a functioning hypothalamus, a structure at the base of the brain that governs certain bodily functions, such as blood pressure and appetite.

It’s an challenging that speaks directly to our idea of what divides life and death. There is no question that any of the patients will recover, regardless of any residual activity detected in their brain.

But it prompts the question of what sort of brain activity we consider human enough to constitute life.

Of course, the issue is compounded by the importance of life-saving organ donation operations, for which suitable organs are almost always in short-supply.